Rotation Detection Device Using Magnetic Concentrator
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Solution Overview
Problem
Conventional rotation detection devices face challenges in miniaturization due to the limited separation distance between magnetic detection elements, which restricts their manufacturing cost and arrangement flexibility.
Innovation Solution
Incorporating a magnetic concentrator between or on both ends of the magnetic detection elements to induce and process variations in the magnetic flux density in the radial and circumferential directions, allowing for compact sensor design and improved dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between magnetic detection elements is increased to obtain sufficient signal intensity, then the signal quality is improved, but the sensor IC size increases and miniaturization is hindered
Solution Approach 1:
A magnetic concentrator is introduced as an intermediary component between the magnet and the magnetic detection elements. This concentrator focuses and guides the magnetic flux from the magnet toward the detection elements, enhancing the magnetic field intensity at the detection points without requiring increased separation distance. The concentrator acts as a mediator that optimizes magnetic flux distribution, enabling high-quality signals within a compact sensor IC footprint.
Solution Approach 2:
The invention changes the magnetic field distribution parameters by introducing the magnetic concentrator, which alters the flux density pattern. Instead of relying on geometric separation to achieve sufficient signal intensity, the system modifies the magnetic field parameters through the concentrator's flux-guiding properties, enabling effective detection within reduced dimensional constraints.
2Measurement precision
If the distance between magnetic detection elements is increased to obtain sufficient variation in magnetic flux density, then the detection accuracy is improved, but the arrangement flexibility and manufacturing cost are worsened
Solution Approach 1:
The magnetic concentrator serves as a mediator that enables accurate detection without requiring large element separation. By concentrating and directing magnetic flux lines toward the detection elements, it ensures sufficient magnetic flux density variation is induced at the detection points even when elements are positioned closely together, thereby maintaining detection accuracy while improving manufacturability and arrangement flexibility.
Solution Approach 2:
The magnetic concentrator creates localized regions of enhanced magnetic flux density at the detection element positions. This local quality enhancement ensures that each detection element experiences sufficient magnetic variation for accurate detection, while the overall sensor IC can maintain a compact layout with flexible arrangement options for manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables miniaturization of the sensor IC, enhances dynamic range, and increases the freedom in sensor arrangement, reducing production costs and improving detection accuracy.
Implementation Method 1
a magnetic concentrator that induces, in the radial direction of the gear, a component in a circumferential direction of the gear in the magnetic flux density on detection surfaces of the magnetic detection elements
Data Source
AI summary
To provide a rotation detection device that has a miniaturized sensor IC in comparison with a prior art.A rotation detection device includes: a magnet that forms a magnetic field toward a tooth surface of a gear; and a sensor disposed between the magnet and the gear, the sensor including: at least a pair of magnetic detection elements x1 and x2 that outputs signals according to a magnetic flux density in a radial direction of the gear; and a magnetic concentrator that induces, in the radial direction of the gear, a component in a circumferential direction of the gear in the magnetic flux density on detection surfaces of the magnetic detection elements x1 and x2, the sensor detecting a variation in a magnetic flux density accompanying the rotation of the gear.